Remove unused runc files

We no longer use runc code to read network I/O usage. This lets
us remove a lot of vendored code.

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #425
Approved by: rhatdan

vendor/github.com/opencontainers/runc/libcontainer/cgroups/fs/devices.go

@@ -1,80 +0,0 @@
-// +build linux
-
-package fs
-
-import (
-	"github.com/opencontainers/runc/libcontainer/cgroups"
-	"github.com/opencontainers/runc/libcontainer/configs"
-	"github.com/opencontainers/runc/libcontainer/system"
-)
-
-type DevicesGroup struct {
-}
-
-func (s *DevicesGroup) Name() string {
-	return "devices"
-}
-
-func (s *DevicesGroup) Apply(d *cgroupData) error {
-	_, err := d.join("devices")
-	if err != nil {
-		// We will return error even it's `not found` error, devices
-		// cgroup is hard requirement for container's security.
-		return err
-	}
-	return nil
-}
-
-func (s *DevicesGroup) Set(path string, cgroup *configs.Cgroup) error {
-	if system.RunningInUserNS() {
-		return nil
-	}
-
-	devices := cgroup.Resources.Devices
-	if len(devices) > 0 {
-		for _, dev := range devices {
-			file := "devices.deny"
-			if dev.Allow {
-				file = "devices.allow"
-			}
-			if err := writeFile(path, file, dev.CgroupString()); err != nil {
-				return err
-			}
-		}
-		return nil
-	}
-	if cgroup.Resources.AllowAllDevices != nil {
-		if *cgroup.Resources.AllowAllDevices == false {
-			if err := writeFile(path, "devices.deny", "a"); err != nil {
-				return err
-			}
-
-			for _, dev := range cgroup.Resources.AllowedDevices {
-				if err := writeFile(path, "devices.allow", dev.CgroupString()); err != nil {
-					return err
-				}
-			}
-			return nil
-		}
-
-		if err := writeFile(path, "devices.allow", "a"); err != nil {
-			return err
-		}
-	}
-
-	for _, dev := range cgroup.Resources.DeniedDevices {
-		if err := writeFile(path, "devices.deny", dev.CgroupString()); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-func (s *DevicesGroup) Remove(d *cgroupData) error {
-	return removePath(d.path("devices"))
-}
-
-func (s *DevicesGroup) GetStats(path string, stats *cgroups.Stats) error {
-	return nil
-}